SQLite

    extern void sqlite3CodecGetKey(sqlite3*, int, void**, int*);
    int nKey;
    char *zKey;
    sqlite3CodecGetKey(db, 0, (void**)&zKey, &nKey);
    if( nKey ) db->nextPagesize = 0;
  }
#endif

  rc = execSql(db, pzErrMsg, "PRAGMA vacuum_db.synchronous=OFF");
  if( rc!=SQLITE_OK ) goto end_of_vacuum;

  /* Begin a transaction and take an exclusive lock on the main database
  ** file. This is done before the sqlite3BtreeGetPageSize(pMain) call below,
  ** to ensure that we do not try to change the page-size on a WAL database.
  */
  rc = execSql(db, pzErrMsg, "BEGIN;");
  if( rc!=SQLITE_OK ) goto end_of_vacuum;
  rc = sqlite3BtreeBeginTrans(pMain, 2);
  if( rc!=SQLITE_OK ) goto end_of_vacuum;

  /* Do not attempt to change the page size for a WAL database */
  if( sqlite3PagerGetJournalMode(sqlite3BtreePager(pMain))
                                               ==PAGER_JOURNALMODE_WAL ){
    db->nextPagesize = 0;
  }

  if( sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain), nRes, 0)
   || (!isMemDb && sqlite3BtreeSetPageSize(pTemp, db->nextPagesize, nRes, 0))
   || NEVER(db->mallocFailed)
  ){
    rc = SQLITE_NOMEM;
    goto end_of_vacuum;
  }





#ifndef SQLITE_OMIT_AUTOVACUUM
  sqlite3BtreeSetAutoVacuum(pTemp, db->nextAutovac>=0 ? db->nextAutovac :
                                           sqlite3BtreeGetAutoVacuum(pMain));
#endif





  /* Query the schema of the main database. Create a mirror schema
  ** in the temporary database.
  */
  rc = execExecSql(db, pzErrMsg,
      "SELECT 'CREATE TABLE vacuum_db.' || substr(sql,14) "
      "  FROM sqlite_master WHERE type='table' AND name!='sqlite_sequence'"
      "   AND rootpage>0"

    sz = pWal->hdr.szPage;
    sz = (sz&0xfe00) + ((sz&0x0001)<<16);
    testcase( sz<=32768 );
    testcase( sz>=65536 );
    iOffset = walFrameOffset(iRead, sz) + WAL_FRAME_HDRSIZE;
    *pInWal = 1;
    /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
    return sqlite3OsRead(pWal->pWalFd, pOut, (nOut>sz ? sz : nOut), iOffset);
  }

  *pInWal = 0;
  return SQLITE_OK;
}

# 2012 February 28
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL" mode.
#
# Specifically, it tests the case where a connection opens an empty
# file. Then, another connection opens the same file and initializes
# the connection as a WAL database. Following this, the first connection
# executes a "PRAGMA page_size = XXX" command to set its expected page
# size, and then queries the database.
#
# This is an unusual case, as normally SQLite is able to glean the page
# size from the database file as soon as it is opened (even before the
# first read transaction is executed), and the "PRAGMA page_size = XXX"
# is a no-op.
#
set testdir [file dirname $argv0]
source $testdir/tester.tcl
set ::testprefix wal8

db close
forcedelete test.db test.db-wal

sqlite3 db test.db
sqlite3 db2 test.db

do_test 1.0 {
  execsql {
    PRAGMA journal_mode = wal;
    CREATE TABLE t1(a, b);
    INSERT INTO t1 VALUES(1, 2);
  } db2
} {wal}

do_catchsql_test 1.1 {
  PRAGMA page_size = 4096;
  VACUUM;
} {0 {}}

db close
db2 close
forcedelete test.db test.db-wal

sqlite3 db test.db
sqlite3 db2 test.db

do_test 2.0 {
  execsql {
    CREATE TABLE t1(a, b);
    INSERT INTO t1 VALUES(1, 2);
    PRAGMA journal_mode = wal;
  } db2
} {wal}

do_catchsql_test 2.1 {
  PRAGMA page_size = 4096;
  VACUUM;
} {0 {}}

db close
db2 close
forcedelete test.db test.db-wal

sqlite3 db test.db
sqlite3 db2 test.db

do_test 3.0 {
  execsql {
    PRAGMA journal_mode = wal;
    CREATE TABLE t1(a, b);
    INSERT INTO t1 VALUES(1, 2);
  } db2
} {wal}

do_execsql_test 3.1 {
  PRAGMA page_size = 4096;
  SELECT name FROM sqlite_master;
} {t1}

finish_test